1. Field of the Invention
This invention relates to a copier to read an original image by an image sensor composed of charge couple device (CCD) and others, and to copy it on a copying paper by a printer such as a laser beam printer.
2. Description of the Prior Art
In a conventional copier, image signals read by an image sensor have been binary-coded, supplied to a laser beam printer or the like and copied on a copying paper. In this process, in order to perform reduction, enlargement and editing of the image to be copied, the image signals have been ordinarily entered in a computer, and subjected to the processing of reduction, enlargement and editing of images for a page to be copied on a bit map memory, and thus have been supplied to the printer.
Using a computer for processing image signals has been effective to enhance the ability in reduction, enlargement and editing, but the operation became complicated and the image processing system has been expensive.
To solve the above problems, it may be considered to supply the image signals read by the image sensor directly to the printer without passing through the computer. Usually, reading of an image is started ahead of an effective image region. That is, reading of the image is started from a blank part before the effective image region. In addition, when reducing the size of the image, as the read image signals are sampled according to a reduction rate and a copying paper size or similarly processed, the starting address of the effective image region cannot be decided automatically when stored in an image memory which is a line memory for interface to supply the read image signals or its reduced image signals to the printer (called merely an image memory hereinafter).
On the other hand, the printer is designed to read the image signals from address 0 of the image memory.
Therefore, in order to directly read out the image signals stored in the image memory from the printer side, it has been necessary to change the starting address of the image memory in which the image signals of the effective image region have been stored; otherwise the image signals can not be supplied correctly to an image region of the printer side.